would the server you are contacting in your LAN be the one running WinGate VPN?
If so, then you are correct about your licensing, but if not, you would need to go the next license size on the gateway, since it won't publish a route to its internal network if the license size is only 1.
in terms of purchasing, our main distributor in the UK is Zen Software -
http://www.zensoftware.co.uk
Adrien